From c6bb8ad8328779e6c59d34f001a2f145c0eae441 Mon Sep 17 00:00:00 2001
From: Jay Kickliter <jay@kickliter.com>
Date: Tue, 14 Mar 2023 12:11:54 -0600
Subject: [PATCH] Don't reduce when target cell is smaller than leaf cell

---
 src/node.rs | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/src/node.rs b/src/node.rs
index e603f5d..db47e54 100644
--- a/src/node.rs
+++ b/src/node.rs
@@ -150,12 +150,10 @@ impl<V> Node<V> {
         V: Copy,
         F: FnMut(u8, &[V]) -> V,
     {
-        if let Self::Leaf(val) = self {
-            return Some(*val);
-        }
-
         match (digits.next(), self) {
-            (Some(_digit), Self::Leaf(_)) => unreachable!(),
+            // Can't reduce when the target cell is higher resolution
+            // than this leaf node.
+            (Some(_digit), Self::Leaf(_)) => None,
             (Some(digit), Self::Parent(children)) => match &children.as_slice()[digit as usize] {
                 Some(node) => node.reduce(res + 1, digits, f),
                 None => None,